So the lead went from Romney to Bachmann to Perry to Cain to Gingrich to Paul and back to Romney. That is waaaaaaaaay more complicated than Tinker to Evers to Chance. Seven leaders in seven months. And that doesn't even count the boomlets for Donald Trump at the beginning, and Rick Santorum at the end.

And it's not as though we saw some kind of "character development" in these characters that would account for the change, as if the Iowa race were like some Stendhal novel. The only change that I saw in any of them is that on November 28, when he was ahead in the polls, Newt Gingrich was a sour megalomaniac, and on January 3, when he came in fourth, Gingrich was a bitter megalomaniac. Sour, bitter, what's the difference?

Also, leaving Herman Cain aside, there were no extraordinary revelations about any of the Republican candidates that could possibly account for their rise and fall. For instance, I gently noted on December 15 that Newt Gingrich is "a philanderer; a corporate shill; a crass greedhead; an egomaniac; and a cranky, crabby, crotchety, caustic, cantankerous, choleric cus." None of that was exactly news. I could have said the same thing about Newt Gingrich on December 15, 1995, and it wouldn't have surprised anyone.

I looked at those Iowa polling numbers again and again, and I asked myself what possible rational explanation there could be for them. And then I realized that there is no possible rational explanation. Only an irrational one.

And it's not the candidates. It's their voters.

Let's see. Severe highs and lows. Violent mood swings. One day, a person thinks that someone is the messiah, and a week later, the devil. And did you see the audience during the Iowa Republican debates? Violent temper tantrums. Inexplicable angry outbursts.

Hmmmmm. What does that sound like?

It sounds like manic depression to me.

All of those manic depressives, about a third of the vote, were forced to choose among Romney, Santorum, Paul, Gingrich, Perry, Bachmann, Cain and Huntsman. But the only candidate who they really could have related to would have been the late, great Thomas Eagleton. (George McGovern's 1972 running mate for 18 days, until all that nasty stuff about electroshock therapy came out.)

I don't know why this would surprise anyone. Roughly 10% of the population of the United States is on anti-depressants. And only 4% of the population of Iowa actually voted in the 2012 Republican caucuses. Just who did you think those 4% were?

So now I understand it. Romney won the paranoid vote, everyone who thinks that the brown people are trying to steal all their stuff. Why? Because no one is more white than Mitt Romney. As I said earlier today, it's as though Romney is on a strict diet of sour cream and cottage cheese, small curds only.

Perry and Bachmann split the schizophrenic vote, all the people who hear a voice in their head, and think that it's God. Because Perry and Bachmann can listen to the radio whenever they want to, even when it's turned off.

Ron Paul got the obsessive-compulsive vote, the folks who think that America is like some kind of mechanical wind-up toy, and the Articles of the Constitution are the gears.

And Santorum ended up with the manic-depressive vote. Maybe because they like the way that Santorum cries in public. Boehner was their second choice.

By the way, I'm not the first person to notice this about the other side. Noted Nixon-hater Philip K. Dick actually wrote a novel about this in 1964, called Clans of the Alphane Moon. Except that Dick placed that story in outer space, not Iowa. Minor difference.

Anyway, I'll tell you one thing. If these are the kind of people who are choosing one of the two major-party candidates for iresident this year, then I'm voting for the other guy. I'm definitely voting for the other guy.